1. Field of the Invention
The present invention relates to a medical instrument preferable for fluorescence observation.
2. Description of the Related Art
Recently, attention has been focused on a cancer diagnosis technique using a molecular target drug. The technique is such that, after spraying or injecting a fluorescence probe (fluorescence medicine) targeting a biological protein which specifically appears in a cancer cell on or into a target site of a living body, it is determined whether cancer exists or not on the basis of fluorescence emitted at the target site. The technique is useful for an early detection of cancer in a field of digestive tracts.
Diagnosis using the technique is possible in an endoscope apparatus. That is, by radiating excitation light from a light source apparatus to an object and catching fluorescence from fluorescence medicine accumulated in cancer, diagnosis of existence of cancer or qualitative diagnosis, such as diagnosis of degree of malignancy, is performed. Note that Japanese Patent Application Laid-Open Publication No. 2009-95538 discloses an electronic endoscope capable of generally performing both of normal white color light observation and fluorescence observation.